KR20240049718A - Charging device using heterogeneous battery - Google Patents

Abstract

A charging device using heterogeneous batteries is disclosed. The disclosed charging device includes a heating cable surrounding a lithium-ion battery, an iron phosphate battery disposed around the lithium-ion battery to selectively supply power to the heating cable depending on the temperature of the lithium-ion battery, and A temperature control module connected to a heating cable to control the temperature of the heating cable, a direct current/direct current (DC/DC) converter for boosting the voltage of an external power source and supplying it to the iron phosphate battery, and the lithium ion battery, It includes a case formed of aluminum material and accommodating the heating cable, the iron phosphate battery, the temperature control module, and the direct current/direct current converter therein. Therefore, the charging device of the present invention has the effect of solving the difficulty of charging at low temperatures and increasing charging efficiency by supplying current through a heating pad with a built-in heating wire surrounding the main battery with an external power source and a power source from a heterogeneous battery.

Description

Charging device using heterogeneous batteries {CHARGING DEVICE USING HETEROGENEOUS BATTERY}

The present invention relates to a charging device using heterogeneous batteries, and more specifically, to a charging device that can reduce discharge of the main rechargeable battery and increase charging efficiency by using heterogeneous batteries. More specifically, the present invention relates to a charging device that can reduce the discharge of the main rechargeable battery and increase charging efficiency. More specifically, the present invention relates to a charging device using a heterogeneous battery ( In general, it relates to a charging device that can reduce discharge and increase charging efficiency by increasing the temperature of the main rechargeable battery using external power and heterogeneous battery power at sub-zero temperatures (below 0°C).

Batteries that can be recharged and reused today include lithium-ion (Li-ion) batteries (also known as ternary batteries, NCM batteries) and lithium iron phosphate batteries (also simply referred to as 'iron phosphate batteries'). Among these, lithium-ion batteries in particular are more expensive than iron phosphate batteries, but have high energy density and can be charged quickly, so they are used in a variety of applications such as high-performance electric vehicles, cell phones, laptops, PCs, and power tools. Lithium-ion (Li-ion) batteries are batteries that convert chemical energy into electrical energy through a redox reaction between anode (+) and cathode (-) materials. Due to their superior performance, they have particularly large limitations on volume and weight. It is widely used in portable products. As shown in Figure 1, most lithium-ion batteries use lithium manganese cobalt compounds for the positive electrode (+) and graphite for the negative electrode (-). After installing a separation membrane in the middle, atoms and It is filled with a salt electrolyte that facilitates the movement of electrons. However, as the external temperature of the battery decreases, the electrolyte structure gradually hardens, and as a result, resistance increases, hindering the movement of the anode material and making charging difficult. In winter, when the external temperature of the battery drops below freezing, charging may become impossible in severe cases. As such, performance decreases significantly depending on temperature and there is a risk of explosion due to pressure, so special caution and ensuring safety are required. To this end, many measures are being taken to increase the temperature of the battery so that electrons and atoms inside the battery can move freely in order to increase battery charging efficiency even at low temperatures as at room temperature.

Conventional technologies for increasing charging efficiency by increasing the temperature of the battery include Republic of Korea Patent Publication No. 10-2013-0009698 (published on January 23, 2013, prior art 1), Republic of Korea Patent Publication No. 10-2017-0119526 (published on October 27, 2017, prior art). Technology 2), Republic of Korea Patent No. 10-2130723 (registered on June 30, 2020, prior art 3), etc. The prior art 1 relates to a battery temperature control system and a driving method thereof, which is a method of increasing the temperature of the main battery by supplying energy to the driving motor using the main battery through a heating pad containing a heating wire. However, in prior art 1, the driving motor receives electrical energy from the main battery, which is the battery to be charged, and converts it into mechanical energy to operate the heating wire to increase the temperature of the main battery. Therefore, the energy of the external power source that charges the main battery is used. If is small or absent, or if the charge remaining in the main battery is low, the driving motor cannot be driven properly and the heating element cannot be operated stably. In addition, in the case of prior art 1, the driving motor is operated with the electric energy of the main battery to operate the heating wire, so there is an advantage in that a separate external power source is not required, but it is difficult to properly charge it due to the power consumption for operating the driving motor. There is a disadvantage in that the charging time of the main battery is delayed and it is difficult to increase the charging efficiency of the main battery.

The above prior art 2 relates to a temperature control device and method for an auxiliary battery pack. Although it is a method of increasing the temperature by utilizing the energy of the rechargeable battery as a heat ray, when the external power is cut off, the heat ray only operates with the charging energy of the rechargeable battery. The disadvantage is that the heating element does not work when the battery is discharged.

The prior art 3 relates to a heated built-in battery, which is a method of generating electricity from the power source of an electric car or two-wheeled vehicle and charging the built-in battery through a heated wire connected to it. This is a method of charging the built-in battery when the car or two-wheeled vehicle stops. It has the disadvantage of not being able to supply energy to the connected heating wire.

Republic of Korea Public Patent No. 10-2013-0009698 (published on January 23, 2013) Republic of Korea Open Patent No. 10-2017-0119526 (published on October 27, 2017) Republic of Korea registered patent 10-2130723 (registered on June 30, 2020)

The problem that the present invention aims to solve is to improve charging efficiency at low temperatures by supplying current through a heating pad with a built-in heating wire that surrounds the main battery with an external power source and a power source from a heterogeneous battery in order to improve the problems of prior technologies for increasing the temperature of the battery. The goal is to provide a charging device using heterogeneous batteries that can be upgraded.

A charging device according to an aspect of the present invention for solving the above problem includes a heating cable 140 surrounding a lithium-ion battery 130, and selectively powering the heating cable depending on the temperature of the lithium-ion battery. An iron phosphate battery 120 disposed around the lithium-ion battery to supply an iron phosphate battery 120, a temperature control module 150 connected to the heating cable to control the temperature of the heating cable, and a temperature control module 150 for controlling the temperature of the heating cable, and boosting the voltage of the external power source to A DC/DC converter 160 for supplying to an iron phosphate battery, the lithium-ion battery, the heating cable, the iron phosphate battery, the temperature control module, and the DC/DC converter are accommodated therein and are made of aluminum material. It is characterized by including a case 110 that is.

According to one embodiment, the temperature control module includes a temperature sensor for detecting the temperature of the lithium-ion battery and is located between the DC/DC converter and the iron phosphate battery, so that the temperature of the lithium-ion battery is adjusted to the temperature. When the temperature drops below the preset temperature in the control module, power from the iron phosphate battery is supplied to the heating cable to generate heat in the heating cable.

According to one embodiment, the input voltage of the DC/DC converter may be 12.6V, and the output voltage after being boosted may be 14V.

According to one embodiment, the external power source may be either a commercial power source 1821 or a solar panel power source 1811.

According to one embodiment, the charging device includes an input connector 191 located between the external power source and the DC/DC converter to allow connection of the external power source, and an input connector 191 located at a rear end of the lithium-ion battery to connect an external load. It further includes an output connector 192 that allows connection.

According to one embodiment, the charging device further includes a poly switch 170 located between the input connector and the lithium-ion battery, and the poly switch includes a lightning protection element.

According to one embodiment, the charging device further includes a charging state display unit to display the charging state of the lithium-ion battery.

The present invention has the effect of increasing charging efficiency by solving the difficulty of charging at low temperatures by supplying current through a heating pad with a built-in heating wire surrounding the main battery using an external power source and a power source from a heterogeneous battery.

1 is a diagram to explain the charging principle of a lithium-ion battery,
Figure 2 is a diagram showing a simplified electrical equivalent circuit model of a lithium-ion battery;
Figure 3 is a graph showing the SOC-OCV curve, also known as the charge/discharge curve, at high temperature (45°C), room temperature (25°C), and low temperature (-10°C).
Figure 4 shows the resistance (R = Ri + Rp) that changes when discharging at high temperature (55°C), room temperature (25°C), and low temperature (-5°C) after setting the C-rate to 0.04°C. This is a graph shown by measurement,
Figure 5 is a diagram for explaining a charging device using heterogeneous batteries according to an embodiment of the present invention;
Figure 6 is a diagram for explaining the characteristics of an iron phosphate battery, a heterogeneous battery, used in the charging device of the present invention.

The present invention is a technology to prevent performance degradation due to temperature in relation to the performance of lithium-ion batteries. To this end, the internal parameter values of lithium-ion batteries are analyzed in various temperature environments to stabilize them as much as possible.

Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings. It should be noted that the attached drawings and examples are simplified and illustrated with the intention of helping those skilled in the art understand the present invention. And, within this specification, lithium-ion batteries are also referred to as main batteries or rechargeable batteries.

First, with reference to FIGS. 2 to 4 , we will look at basic information related to charging capacity in relation to a lithium-ion battery (main battery or rechargeable battery).

Figure 2 is a diagram showing a simplified electrical equivalent circuit model of a lithium-ion battery. Referring to FIG. 2, the parameters of a lithium-ion battery can be broadly simplified and expressed as external power (Vc), flowing current (Ic), and internal resistance (Rp, Ri). In particular, in the case of lithium-ion batteries filled with electrolyte, in addition to the basic ohmic resistance (Ri), polarization resistance (Rp), which is the resistance of the separator inserted to separate the positive (+) and negative (-) electrodes, occurs. This can be summarized briefly as follows.

Vc = Ic * (Ri + Rp)

Figure 3 shows the SOC-OCV curve, also known as the charge/discharge curve, at high temperature (45°C), room temperature (25°C), and low temperature (-10°C) (temperature values of high temperature, room temperature, and low temperature are examples). It can be seen that the temperature continues to decrease as it decreases from high temperature to low temperature (see IR split voltage drop arrow in FIG. 3). In other words, it can be seen that as the temperature decreases, the IR split voltage value inside the battery decreases, and ultimately the usable capacity of the main battery also decreases.

Figure 4 shows the resistance (R = Ri + Rp) that changes when discharging at high temperature (55°C), room temperature (25°C), and low temperature (-5°C) after setting the C-rate to 0.04°C. This is a graph shown by measurement. As a result of the test, it can be seen that the internal resistance becomes relatively larger as the temperature decreases, regardless of the C-rate of the current.

As can be seen in Figures 3 and 4 above, the resistance (R) inside the rechargeable battery (main battery) does not change significantly at high temperature and room temperature, but increases significantly at low temperature, and is divided into increased resistance. It can be seen that the voltage (OCV) is lowered and the usage of the rechargeable battery is greatly reduced. Therefore, by increasing the internal temperature of the rechargeable battery as the temperature goes down and reducing resistance, a constant battery capacity can be maintained regardless of the external temperature.

As mentioned earlier, the present invention basically increases the temperature of a lithium-ion battery, which is the main battery (or rechargeable battery) to be charged, by using the power of a lithium iron phosphate (LiFePo ₄ ) battery (iron phosphate battery), which is a heterogeneous battery. This is about ways to increase charging efficiency. Iron phosphate batteries are relatively superior to lithium-ion batteries in terms of temperature characteristics, voltage sustainment characteristics, and charge/discharge frequency characteristics. Accordingly, the present invention increases charging efficiency by increasing the temperature of the lithium-ion battery by driving a heating cable using the power of an iron phosphate battery having these characteristics.

FIG. 5 is a diagram for explaining a charging device using heterogeneous batteries according to an embodiment of the present invention, and features of the charging device of the present invention are explained with reference to FIG. 5 .

The charging device of the present invention includes a case 110, a lithium ion battery 130, an iron phosphate battery 120, a heating cable 140, a temperature control module 150, and a direct current/direct current converter 160. .

The case 110 accommodates a lithium-ion battery 130, a heating cable 140, an iron phosphate battery 120, a temperature control module 150, and a direct current/direct current converter 160, and contains aluminum with excellent thermal conductivity. It is formed from materials.

The lithium-ion battery 130 is a main battery, that is, a rechargeable battery, and is composed of a set of a plurality of battery cells.

The iron phosphate battery 120 is a battery for selectively supplying power to the heating cable 140 when the temperature of the lithium ion battery 130 falls below a preset temperature, and is different from the lithium ion battery 130. It is a type of battery with different characteristics, that is, a heterogeneous battery. As mentioned earlier, iron phosphate batteries are relatively superior to lithium-ion batteries in terms of temperature characteristics, voltage sustainment characteristics, and charge/discharge frequency characteristics. The iron phosphate battery 120 is located around the lithium ion battery 130 inside the case 110.

The heating cable 140 is a component that surrounds the lithium-ion battery 130. When the temperature of the lithium-ion battery 130 falls below a preset standard temperature, it receives power from the iron phosphate battery 120 and generates heat. It functions to increase the charging efficiency of the lithium-ion battery 130 by raising the temperature of the lithium-ion battery 130. The heating cable 140 may be configured as a heating pad (not shown) type with a heating wire inside and surrounding the lithium-ion battery 130. The heating wire cable 140 uses the low power of the iron phosphate battery 120, a heterogeneous battery, to generate heat with high efficiency through the heating wire.

The temperature control module 150 is connected to the heating cable 140 and controls the temperature of the heating cable 140. The temperature control module 150 includes a temperature sensor (not shown) for detecting the temperature of the lithium ion battery 130, and is located between the DC/DC converter 160 and the iron phosphate battery 120, When the temperature of the battery 130 falls below the temperature preset in the temperature control module 150, power from the iron phosphate battery 120 is supplied to the heating cable 140 to generate heat. The temperature control method in the temperature control module 150 is, for example, to detect the temperature of the lithium-ion battery 130 in real time through a temperature sensor, and when it is below a preset reference temperature, the iron phosphate battery 120 side and the heating cable 140 ) is switched to form a closed circuit and continues for a certain period of time, and then, if it is higher than the preset operating temperature, the temperature control module 150 causes the iron phosphate battery 120 to receive voltage from the DC/DC converter 160. It may operate in a switching manner so that it can be charged, but is not limited to this example.

The DC/DC converter 160 is a component that boosts the voltage of the external power sources 1811 and 1821 and supplies it to the iron phosphate battery 120. The primary side voltage, that is, the input voltage, of the DC/DC converter 160 is 12.6V, and the secondary side voltage, that is, the output voltage after being boosted, is 14V.

The external power source may be either a commercial power source 1821 or a solar panel power source 1811. Alternatively, the external power source may be the power source of another external battery or charging device (not shown). When the external power source is a 220V AC commercial power source (1821), an AC/DC adapter is further provided between the commercial power source (1821) and the input connector 170 to provide an appropriate voltage (12.6V) for charging the lithium-ion battery 130. It is lowered to and provided as a lithium-ion battery (130). When the external power source is from the solar panel 1811, a solar charge controller 1812 is further provided between the solar panel 1811 and the input connector 1911 to adjust the voltage for charging the lithium-ion battery 130. It is adjusted to (12.6V) and provided as a lithium-ion battery (130). In the case of using the solar panel 1811 and the solar charge controller 1812 on the external power side, the solar charge controller 1821 estimates the maximum power point at a voltage of 13V or more collected from the solar panel 1811. (MPPT: Maximum Power Point Tracking) rectifies it to 12.6V.

In addition, the dropped voltage (12.6V) is boosted to 14V by the DC/DC converter 160 and used to charge the iron phosphate battery 120. Accordingly, the charging voltage of the lithium ion battery 130 is 12.6V, and the charging voltage of the iron phosphate battery 120 is 14V.

Additionally, the charging device of the present invention includes an input connector 191 and an output connector 192. The input connector 191 is located between the external power sources 1811 and 1821 and the DC/DC converter 160 to allow connection of the external power sources 1811 and 1821. The output connector 192 is located at the rear of the lithium-ion battery 130 and allows connection of an external load. Although not shown in FIG. 5, contrary to the above connection, an external power source may be connected to the output connector 192 and an external load may be connected to the input connector 191.

Additionally, the charging device of the present invention further includes a poly switch 170. The poly switch 170 is located between the input connector 191 and the lithium-ion battery 130 and includes a lightning protection element (not shown) to protect the charging device when an external high voltage is applied. The poly switch 170 is an automatic recovery fuse that protects various components inside the charging device and a battery monitoring system (BMS) (not shown) for charge and discharge management from high voltage such as lightning.

In addition, the charging device of the present invention may further include a charging state display unit (not shown) for displaying the charging state of the lithium ion battery 130.

The overall operation process from the assembly process of the charging device of the present invention is described as follows.

First, connect the charging power cable (not shown) of the external power source (1811, 1821) containing the (+) wire and (-) wire to the cable port (not shown) of the case 110 and fasten it tightly. Create two cable ports on the front and rear sides of the case 110 and install a Φ20 power connector. It can be easily connected to an external power source through the front cover power connector (corresponding to the input connector), and the rear cover power connector (corresponding to the output connector) can be easily connected and expanded when the battery capacity needs to be increased.

In addition, select an AWG wire of the appropriate thickness for the power connector installed on the front cover (not shown) and the rear cover (not shown), connect it to the + terminal and - terminal, and then use the shortest length to manage the battery of the lithium-ion battery 130. Connect the 12.6V and GND printed parts to the PCB of the module (BMS) (not shown) by soldering, extend the wire and connect it to the + and - terminals of the DC/DC converter, and connect it to the power connector on the back cover. Connect.

In addition, the DC/DC converter 160 boosts the supplied input voltage of 12.6V to create 14V and connects it to the + and - input terminals of the temperature control module 150 and the battery management module (not shown) of the iron phosphate battery. Connect to the + and - input terminals. Afterwards, the lithium ion battery 130 is wrapped around the heating cable 140 and the + and - terminals are connected to the load terminal of the temperature control module 150.

The charging device of the present invention places a connector for exchanging external power on the input cover and output cover, so that it can be charged by connecting to an external power source of 12.6V in normal times, and when charging is completed, the battery is inserted and connected inside. It protects the battery from overcharging by blocking the input power to the printed circuit board of the management module (BMS) so that it is no longer charged and remains charged. In order to easily determine the level of charge of the lithium-ion battery 130, the previously mentioned charge status display unit (not shown) is further provided.

In addition, it can be connected to electronic devices through the power connector (input connector) installed on the back cover, and if more charging is needed, it can be connected in series with the input terminal of another battery to easily charge multiple batteries through a single input voltage. there is. If the temperature of the lithium-ion battery 130 is higher than the operating temperature preset in the temperature control module 150, the lithium-ion battery 130 and the iron phosphate battery 120 remain charged by receiving power from an external power source. do. However, when the temperature is lower than the reference temperature preset in the temperature control module 150, the heating cable 140 operates to generate heat and thus increases the temperature of the lithium ion battery 130.

When the external power (1811, 1821) is supplied, the external power (1811, 1821) charges the lithium-ion battery (130) and the iron phosphate battery (120). At this time, the heated cable (140) connected to the iron phosphate battery (130) ) heats the lithium-ion battery 130 so that charging can continue stably without decreasing charging efficiency. When the external power sources 1811 and 1821 are not supplied, the lithium ion battery 130 and the iron phosphate battery 120 stop charging. Even in this state, the iron phosphate battery 120 supplies the energy it has charged to the heating wire to heat the lithium-ion battery 130 to prevent the performance of the lithium-ion battery 130 from deteriorating. The heating cable 140 continues to generate heat until the temperature of the battery is higher than the operating temperature preset in the temperature control module 150. Therefore, if the operating temperature of the temperature control module 150 is set too high (e.g., set to room temperature), the power consumption of the iron phosphate battery 120 increases unnecessarily, and thus the characteristics of the lithium-ion battery 130 and phosphoric acid It is advantageous to set it to an appropriate value considering the capacity of the iron battery, etc.

Lastly, referring to FIG. 6, the charging device of the present invention uses an iron phosphate battery 120, a heterogeneous battery, as an energy source for the heating cable 140. As shown, the charging device of the present invention maintains a constant charge of 80% or more for a relatively long time. It has the advantage of being able to supply power. In addition, compared to lithium-ion batteries, they have the advantage of being less expensive, very stable, and having a longer lifespan.

110: case
120: iron phosphate battery
130: Lithium-ion battery
140: heated cable
150: temperature control module
160: DC/DC converter
170: poly switch

Claims (7)

A heated cable (140) surrounding the lithium-ion battery (130);
an iron phosphate battery 120 disposed around the lithium ion battery to selectively supply power to the heating cable depending on the temperature of the lithium ion battery;
a temperature control module 150 connected to the heating cable to control the temperature of the heating cable;
A direct current/direct current (DC/DC) converter 160 for boosting the voltage of an external power source and supplying it to the iron phosphate battery; and
A case 110 that accommodates the lithium ion battery, the heating cable, the iron phosphate battery, the temperature control module, and the direct current/direct current converter and is made of aluminum material; A charging device comprising:
In claim 1,
The temperature control module includes a temperature sensor for detecting the temperature of the lithium-ion battery and is located between the DC/DC converter and the iron phosphate battery, so that the temperature of the lithium-ion battery is set to a temperature preset in the temperature control module. A charging device, characterized in that, when the temperature drops below this level, power from the iron phosphate battery is supplied to the hot wire cable to generate heat in the hot wire cable.
The charging device according to claim 1, wherein the input voltage of the DC/DC converter is 12.6V, and the output voltage after being boosted is 14V.
The charging device according to claim 1, wherein the external power source is one of a commercial power source (1821) and a solar panel power source (1811).
The method of claim 1, wherein the charging device,
An input connector 191 located between the external power source and the DC/DC converter to allow connection of the external power source; and
Characterized in that it further includes an output connector 192 located at the rear of the lithium-ion battery to allow connection of an external load.
The method of claim 5, wherein the charging device,
It further includes a poly switch 170 located between the input connector and the lithium-ion battery,
The poly switch is a charging device, characterized in that it includes a lightning protection element.
The method of claim 1, wherein the charging device,
A charging device, characterized in that it further includes a charging status display unit for displaying the charging status of the lithium ion battery.